SamTrans prepares to roll out 10 electric buses in...

2of27People board a SamTrans bus across from the temporary Transbay Terminal in the Rincon Hill neighborhood of San Francisco, CA, on Thursday May 25, 2017.Photo: Michael Short, Special to the Chronicle

3of27People board a SamTrans bus across from the temporary Transbay Terminal in the Rincon Hill neighborhood of San Francisco, CA, on Thursday May 25, 2017.Photo: Michael Short, Special to the Chronicle

4of27People board a SamTrans bus across from the temporary Transbay Terminal in the Rincon Hill neighborhood of San Francisco, CA, on Thursday May 25, 2017.Photo: Michael Short, Special to the Chronicle

5of27Passengers waiting for their SamTrans bus in San Mateo County can now check on 511.org or call 5-1-1 to get real-time arrival information for their bus.

6of27Click through this slideshow for the cities where residents have the longest commutes. Photo: Santiago Mejia / The Chronicle

A new battery-powered electric bus pulled out of the driveway at SamTrans’ San Carlos headquarters Monday morning, its motor purring as it turned left onto El Camino Real.

Designed by Burlingame manufacturer Proterra Inc., the bus is a replica of 10 that will roll out on the Peninsula next year, the first batch in the agency’s effort to convert its entire fleet to zero emission vehicles by 2032.

It won’t be easy. SamTrans operates more than 300 diesel commuter buses that crisscross San Mateo County, each with a life span of about 12 years. The new electric buses cost $700,000 a piece — about $200,000 more than a diesel-guzzling model — and the agency will put a contract out for bid each time they order a new bundle.

Yet transit officials and politicians who took an inaugural ride on Tuesday said they are eager to see the change.

“I can hear myself think on this bus,” SamTrans board Chairman Charles Stone said of the new electric shuttle. “It just sounds so much nicer. You don’t have that diesel belching noise or that air brake hissing that you get with the traditional combustion engine.”

The board approved funding for the 10 electric buses in March, declaring at that time that SamTrans would never purchase another diesel bus — a promise the board may have to keep to meet Gov. Jerry Brown’s 2040 deadline for all transit agencies to eliminate carbon emissions.

San Mateo is behind San Francisco, where all streetcars run on electric wires. Muni switched its regular fleet to diesel hybrids in 2012, but the SFMTA board dreams of going all electric in the next few years. Other early adopters include San Jose and Stockton, which aims to convert all its city buses to electric models by 2025, given that air pollution is a huge concern in the Central Valley.

Proterra CEO Ryan Popple compared the new bus to a Chevy Volt or Tesla, because it has no fuel tank. At 29,900 pounds, its body is about 4,000 pounds lighter than a regular steel bus, making up for the weight of four battery packs mounted in the chassis.

Putting those batteries beneath the floor gives the bus a low center of gravity so it can handle turns easily, said Matt Horton, Proterra’s chief commercial officer.

“It’s a powerful vehicle,” he bragged, pointing out features as he strutted along the bus’s floor. Its driver seat faces a large, lit-up dashboard with a battery gauge. In the back, sunlight trickles in through a rearview window — a space that would normally be filled by the engine or air conditioning system.

The electric bus’s motor weighs less than 200 pounds but does the work of a 2,000-pound diesel engine burning about a quarter-gallon of fuel every mile, Popple said. The emissions from that fuel build up, with typical city buses driving up to 40,000 miles a year.

So, just one electric bus saves SamTrans 10,000 gallons of diesel fuel annually, which is enough to offset the added cost of the bus over a four-year period.

In addition to their lean but muscular motors, SamTrans’ new battery-powered vehicles also have USB charging ports next to all the double seats, low floors to accommodate wheelchair ramps, and wheelchair restraints that are more secure than the existing ratchets.

And they run better, said bus driver Ariel Hale, who recently spent a day training to drive the new vehicles.

“It’s more like driving a car,” he said. “The acceleration is a little smoother. So is the brake.”

Rachel Swan covers transportation for The Chronicle. She joined the paper in 2015 and has also reported on politics in Oakland and San Francisco.

Previously, Rachel held staff positions at the SF Weekly and the East Bay Express, where she covered technology, law and the arts. She holds a Bachelor’s degree in rhetoric from the University of California, Berkeley.